Regarding USJ... of course Disney notices, but I highly doubt we're looking at a scenario where anyone - Disney, Universal or anyone else - feels like the parks seriously competes across continents.
USJ is primarily competing with TD and DS. The WDW parks are primarily competing with USO and IOA. And DL and DCA are primarily competing USH.
Disney is not filled with braindead people. Of course big growth numbers are noticed and discussed, but people at WDW/TDO are more concerned with the IOA and USO numbers, as they should be, and I think the major growth spurt by USO is definitely noticed. However, I also think the fact that IOA has flatlined says something, i.e. that USO growth didn't improve IOA growth one bit, maybe even on the contrary.
All the projects going on right now - Avatarland and general DAK upgrades, the rumored DHS overhaul, and even DS are all attempts to combat Universal Florida. Whether or not you agree that it's enough, that's a different topic, but saying that Disney doesn't notice/care about the attendance numbers for their biggest competitors is just ignorant.
Personally, I think they should be most focused on the fact that MK is seeing close to a 50% attendance increase over the 3 other parks. That's very tangible growth potential for those parks, and with a good strategy, they should be able to narrow that gap significantly.